/* ============================================================
   Manhattan Academy of Music and Language — landing page
   Single font: Be Vietnam Pro

   Style: Japanese / Swiss editorial restraint.
   Sharp slabs (border-radius 2px), thin rules, generous white
   space, no pills, no fat rounded cards, no colored washes.
   Color is a punctuation mark — used only on the swapped word
   inside a trailer card and the active card's 2px top hairline.
   ============================================================ */

*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --bg: #ffffff;
  --ink: #0a0a0a;
  --ink-2: #2a2a2a;
  --muted: #6a6a6a;
  --muted-2: #9a9a9a;
  --line: #e6e6e6;
  --pill: #f3f3f3;
  --pill-hover: #ebebeb;

  --max: 1180px;
  --pad: clamp(20px, 4vw, 56px);

  /* Swiss restraint: every corner on the page is 2px. */
  --radius: 2px;

  --t-fast: 180ms cubic-bezier(.2, .7, .2, 1);
  --t-med:  360ms cubic-bezier(.2, .7, .2, 1);
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Be Vietnam Pro", system-ui, -apple-system, sans-serif;
  font-weight: 400;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ---------- Topbar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 24px;
  max-width: var(--max);
  margin: 0 auto;
  padding: 18px var(--pad);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-logo {
  width: 44px;
  height: 44px;
  object-fit: contain;
  display: block;
}

.brand-name {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-en {
  font-weight: 800;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.brand-vi {
  font-weight: 400;
  font-size: 12px;
  color: var(--muted);
  font-style: italic;
}

.topnav {
  grid-column: 3;
  display: flex;
  gap: 0;
  justify-self: end;
}

/* Topnav: no pills. Plain text with a subtle 1px underline on
   hover — Swiss editorial, no background washes. */
.topnav a {
  position: relative;
  padding: 8px 2px;
  margin: 0 10px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink-2);
  transition: color var(--t-fast);
}

.topnav a::after {
  content: "";
  position: absolute;
  left: 2px;
  right: 2px;
  bottom: 4px;
  height: 1px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t-fast);
}

.topnav a:hover {
  color: var(--ink);
}

.topnav a:hover::after {
  transform: scaleX(1);
}

/* ---------- Main ---------- */
main {
  width: 100%;
  max-width: none;
  margin: 0;
  padding: 0;
}

/* ---------- Hero ---------- */
.hero {
  width: 100%;
  max-width: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: clamp(4px, 0.8vw, 12px) var(--pad) clamp(56px, 8vw, 96px);
}

.eyebrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  margin: 0 0 6px;
  font-size: 13px;
}

.eyebrow .en {
  font-weight: 700;
  color: var(--ink);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 12px;
}

.eyebrow .vi {
  font-weight: 400;
  color: var(--muted-2);
  font-style: italic;
  font-size: 12px;
}


/* ---------- Tôi Ăn Cơm trailer: shelf of swap modules ---------- */
.tac-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  width: 100%;
}

.tac-library {
  position: relative;
  width: 100%;
  max-width: 1480px;
  height: 960px;
  perspective: 1800px;
  perspective-origin: 50% 50%;
}

/* Each card receives the following CSS custom properties from script.js,
   set per module from modules.js. No per-slot CSS rules — adding cards
   requires NO style edits.

   --accent       : per-card highlight color (becomes border + active word)
   --shelf-x      : px X offset on the shelf
   --shelf-y      : px Y offset
   --shelf-z      : px Z depth
   --shelf-roty   : deg Y rotation
   --shelf-rotz   : deg Z tilt
   --breathe-delay: animation-delay for the idle breathe pulse
*/

.tac-module {
  --accent: var(--ink);
  --shelf-x: 0px;
  --shelf-y: 0px;
  --shelf-z: 0px;
  --shelf-roty: 0deg;
  --shelf-rotz: 0deg;
  --breathe-delay: 0s;
  --shelf-z-index: 1;

  position: absolute;
  top: 50%;
  left: 50%;
  z-index: var(--shelf-z-index);
  width: 340px;
  height: 220px;
  padding: 22px 28px;
  background: #ffffff;

  /* RULE: restraint. Cards are sharp white slabs with subtle neutral
     elevation. The accent color appears ONLY on the swapped word
     itself (and as a single hairline accent on the active card's
     top edge). No colored glows, no halos, no shrines. Aim:
     Japanese / Swiss editorial — the page is mostly white space and
     typography. Don't reintroduce colored shadows. */
  border: none;
  border-radius: 2px;
  cursor: pointer;
  font-family: inherit;
  text-align: left;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transform-style: preserve-3d;
  transform-origin: 50% 50%;
  backface-visibility: hidden;
  will-change: transform;
  box-shadow:
    0 1px 2px rgba(0, 0, 0, 0.04),
    0 14px 36px -14px rgba(0, 0, 0, 0.10);
  transition:
    transform 720ms cubic-bezier(.2, .7, .2, 1),
    box-shadow 720ms cubic-bezier(.2, .7, .2, 1);

  transform:
    translate(-50%, -50%)
    translateX(var(--shelf-x))
    translateY(var(--shelf-y))
    translateZ(var(--shelf-z))
    rotateY(var(--shelf-roty))
    rotateZ(var(--shelf-rotz));
}

/* Hover on ring cards: push forward in Z, soften the inward tilt.
   X/Y stay locked to the ring position — lifting a top-edge card
   would push it off-stage, so we don't touch them. */
.tac-module:hover:not(.is-active) {
  transform:
    translate(-50%, -50%)
    translateX(var(--shelf-x))
    translateY(var(--shelf-y))
    translateZ(calc(var(--shelf-z) + 70px))
    rotateY(calc(var(--shelf-roty) * 0.55))
    rotateZ(var(--shelf-rotz));
}

/* Active state — pulled forward to the very center, larger, with a
   refined neutral elevation. A single 2px accent hairline runs
   along the very top edge as the only colored signature.
   Width is fluid: grows to fit long swap variants (e.g. the full
   "tôi ăn cơm chưa" ADDREM sentence) up to a capped max so the
   shelf behind it stays visible. */
.tac-module.is-active {
  width: auto;
  min-width: 660px;
  max-width: min(92vw, 960px);
  height: auto;
  min-height: 320px;
  padding: 36px 52px 32px;
  transform: translate(-50%, -50%) translateZ(220px) rotateY(0deg) rotateZ(0deg) scale(1.1) !important;
  z-index: 100;
  box-shadow:
    0 1px 2px rgba(0, 0, 0, 0.05),
    0 40px 100px -28px rgba(0, 0, 0, 0.18);
  cursor: pointer;
  gap: 16px;
}

.tac-module.is-active::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--accent);
}

/* When one card is active, the inactive ring cards stay SOLID (never
   transparent — text bleeding through is unreadable). They keep their
   ring position (X/Y) and just recede hard in Z so the active card
   clearly dominates the foreground without visually colliding with
   the surrounding frame. */
.tac-library.has-active .tac-module:not(.is-active) {
  transform:
    translate(-50%, -50%)
    translateX(var(--shelf-x))
    translateY(var(--shelf-y))
    translateZ(calc(var(--shelf-z) - 260px))
    rotateY(var(--shelf-roty))
    rotateZ(var(--shelf-rotz));
}

/* ----- Card content ----- */
.mod-head {
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.mod-kind {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.24em;
  color: var(--muted-2);
  text-transform: uppercase;
}

.mod-target {
  font-size: 16px;
  font-weight: 800;
  color: var(--accent);
  font-style: italic;
}

/* Sentence layout is type-aware.
   - SWAP: 1fr | auto | 1fr grid — the active word stays pinned
     to the card's visual center because left and right contexts
     balance each other (rule: "swapped word always centered").
   - ADD:  flex row, the whole sentence centered as a unit inside
     .mod-word-active. The added particle can land anywhere in
     the sentence, sometimes as a pair (e.g. "có … đâu"), so a
     grid would force the particle off-center or cause overlap.
     Centering the sentence container avoids both. */
.mod-sentence {
  align-items: baseline;
  font-size: 28px;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  margin: 6px 0;
  perspective: 900px;
  width: 100%;
  min-width: 0;
}

.tac-module[data-type="swap"] .mod-sentence {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
}

.tac-module[data-type="add"] .mod-sentence {
  display: flex;
  justify-content: center;
  flex-wrap: nowrap;
}

.mod-side {
  color: var(--ink);
  white-space: nowrap;
  font-weight: 800;
  opacity: 0.75;
}

/* SWAP sides: right-align left · left-align right so the sentence
   reads continuously around the centered active word. */
.tac-module[data-type="swap"] .mod-left  { text-align: right; padding-right: 0.36em; }
.tac-module[data-type="swap"] .mod-right { text-align: left;  padding-left:  0.36em; }

/* ADD sides are always empty (content lives inside
   .mod-word-active as segment children). Collapse them so the
   sentence flex doesn't reserve phantom space. */
.tac-module[data-type="add"] .mod-side { display: none; }

.mod-word-active {
  color: var(--accent);
  display: inline-block;
  white-space: nowrap;
  text-align: center;
  transform-origin: 50% 50%;
  backface-visibility: hidden;
  will-change: transform, opacity;
}

/* ADD: .mod-word-active is a segment container. Segments sit in a
   row with a natural word gap and rotate together with the parent
   during flip. A seg-hit is accent-colored; a seg-mute is neutral
   context. Supporting multiple seg-hit spans in one item is how
   template pairs like "có ... đâu" highlight both halves at once. */
.tac-module[data-type="add"] .mod-word-active {
  display: inline-flex;
  align-items: baseline;
  flex-wrap: nowrap;
  gap: 0.3em;
  white-space: nowrap;
}

.tac-module[data-type="add"] .mod-word-active .seg-hit {
  color: var(--accent);
  font-weight: 800;
}

.tac-module[data-type="add"] .mod-word-active .seg-mute {
  color: var(--ink);
  opacity: 0.75;
  font-weight: 800;
}

@keyframes mod-flip-out {
  0%   { transform: rotateX(0deg);   opacity: 1; }
  100% { transform: rotateX(-90deg); opacity: 0; }
}
@keyframes mod-flip-in {
  0%   { transform: rotateX(90deg);  opacity: 0; }
  100% { transform: rotateX(0deg);   opacity: 1; }
}

.mod-word-active.flip-out {
  animation: mod-flip-out 350ms cubic-bezier(.6, .02, .4, 1) forwards;
}
.mod-word-active.flip-in {
  animation: mod-flip-in 350ms cubic-bezier(.6, .02, .4, 1) forwards;
}

.mod-foot {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 2px;
  text-align: center;
  width: 100%;
  min-width: 0;
}

.mod-foot-en,
.mod-foot-vi {
  display: block;
  width: 100%;
  max-width: 100%;
  min-width: 0;
  overflow-wrap: break-word;
  word-break: break-word;
  hyphens: auto;
}

.mod-foot-en {
  font-size: 12px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.35;
}

.mod-foot-vi {
  font-size: 11px;
  font-style: italic;
  color: var(--muted);
  line-height: 1.35;
}

/* ----- Active-state typographic boost ----- */
.tac-module.is-active .mod-target {
  font-size: 20px;
}

.tac-module.is-active .mod-sentence {
  font-size: clamp(36px, 5vw, 48px);
  margin: 12px 0;
}

.tac-module.is-active .mod-foot-en {
  font-size: 14px;
}

.tac-module.is-active .mod-foot-vi {
  font-size: 12px;
}

.mod-mode {
  display: none;
  margin-top: 8px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted-2);
}

.tac-module.is-active .mod-mode {
  display: inline;
}

/* ----- Close (×) button ----- */
.mod-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 28px;
  height: 28px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: #ffffff;
  font-family: inherit;
  font-size: 18px;
  line-height: 1;
  color: var(--muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 280ms ease, color 200ms ease, border-color 200ms ease, transform 200ms ease;
}

.tac-module.is-active .mod-close {
  opacity: 1;
  pointer-events: auto;
}

.mod-close:hover {
  color: var(--ink);
  border-color: var(--ink);
  transform: scale(1.08);
}

/* ----- Idle breath: a barely-perceptible elevation pulse ----- */
@keyframes tac-breathe {
  0%, 100% {
    box-shadow:
      0 1px 2px rgba(0, 0, 0, 0.04),
      0 14px 36px -14px rgba(0, 0, 0, 0.10);
  }
  50% {
    box-shadow:
      0 1px 2px rgba(0, 0, 0, 0.05),
      0 20px 48px -14px rgba(0, 0, 0, 0.14);
  }
}
.tac-library:not(.has-active) .tac-module {
  animation: tac-breathe 4.2s ease-in-out infinite;
  animation-delay: var(--breathe-delay);
}

.tac-hint {
  display: none;
  margin: 0;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  text-align: center;
}
.tac-hint .en {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}
.tac-hint .vi {
  font-size: 11px;
  font-style: italic;
  color: var(--muted-2);
}

/* tac-link: plain text link with a 1px underline — not a pill. */
.tac-link {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  padding: 4px 0;
  border-bottom: 1px solid var(--ink);
  font-size: 13px;
  font-weight: 700;
  transition: opacity var(--t-fast);
}

.tac-link .en {
  color: var(--ink);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.tac-link .vi {
  color: var(--muted);
  font-size: 11px;
  font-style: italic;
}

.tac-link:hover {
  opacity: 0.7;
}

/* ---------- Pillars ---------- */
/* Pillars: sharp white slabs divided by a 1px vertical rule,
   each titled with a thin top hairline. No rounded corners, no
   background tint, no lift on hover — the content does the work. */
.pillars {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--pad) clamp(72px, 10vw, 140px);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.pillar {
  position: relative;
  padding: clamp(40px, 5vw, 72px) clamp(28px, 4vw, 56px);
  background: #ffffff;
  border-radius: 0;
}

.pillar + .pillar {
  border-left: 1px solid var(--line);
}

.pillar h2 {
  display: flex;
  flex-direction: column;
  margin: 0 0 28px;
  line-height: 1.1;
}

.pillar h2 .en {
  font-weight: 800;
  font-size: clamp(26px, 2.6vw, 34px);
  letter-spacing: -0.02em;
  color: var(--ink);
}

.pillar h2 .vi {
  font-weight: 400;
  font-size: 13px;
  color: var(--muted);
  font-style: italic;
  margin-top: 6px;
}

.pillar-body {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-2);
  max-width: 48ch;
}

.pillar-body-vi {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
  font-style: italic;
  max-width: 52ch;
}

/* ---------- Genre / instrument emphasis ----------
   For Vietnamese musical genres and instruments (hát ru, vọng cổ,
   đàn tranh, hát xẩm, lý con sáo). Italic + bold + a marker-pen
   highlight underline. Color used here is intentional editorial
   punctuation, not a wash — only these named terms carry it. */
.dieu {
  font-style: italic;
  font-weight: 700;
  color: var(--ink);
  background: linear-gradient(
    180deg,
    transparent 0%,
    transparent 62%,
    rgba(232, 178, 56, 0.32) 62%,
    rgba(232, 178, 56, 0.32) 92%,
    transparent 92%
  );
  padding: 0 2px;
  border-radius: 1px;
}

.pillar-body-vi .dieu,
.pub-meta .dieu {
  font-weight: 600;
}

/* ---------- Publications ----------
   A long-form research list. Same Swiss/Japanese restraint as
   pillars: sharp white slabs, 1px hairline rules between items,
   year as a thin tag in the gutter, EN primary VI secondary.
   No rounded corners, no hover lift, no fill. */
.publications {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(64px, 8vw, 120px) var(--pad);
  border-bottom: 1px solid var(--line);
}

.publications-head {
  margin: 0 0 clamp(36px, 4vw, 56px);
  max-width: 64ch;
}

.publications-head h2 {
  display: flex;
  flex-direction: column;
  margin: 0 0 20px;
  line-height: 1.1;
}

.publications-head h2 .en {
  font-weight: 800;
  font-size: clamp(26px, 2.6vw, 34px);
  letter-spacing: -0.02em;
  color: var(--ink);
}

.publications-head h2 .vi {
  font-weight: 400;
  font-size: 13px;
  color: var(--muted);
  font-style: italic;
  margin-top: 6px;
}

.publications-intro {
  margin: 0 0 6px;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-2);
}

.publications-intro-vi {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
  font-style: italic;
}

.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.pub-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: clamp(20px, 3vw, 40px);
  padding: clamp(20px, 2.4vw, 28px) 0;
  border-bottom: 1px solid var(--line);
}

.pub-year {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--muted);
  padding-top: 3px;
}

.pub-body {
  min-width: 0;
}

.pub-title {
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
  margin-bottom: 6px;
  max-width: 72ch;
}

.pub-meta {
  font-size: 13px;
  font-style: italic;
  line-height: 1.5;
  color: var(--muted);
  max-width: 72ch;
}

/* ---------- Apps ----------
   Same Swiss/Japanese restraint as publications: sharp white slabs,
   1px hairline rules between items, two-digit index in the gutter,
   title as a plain text link with a 1px underline on hover. No
   pills, no fill, no halos. Coming-soon items are non-interactive
   and muted — same row, marked by .is-soon. */
.apps {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(64px, 8vw, 120px) var(--pad);
  border-bottom: 1px solid var(--line);
}

.apps-head {
  margin: 0 0 clamp(36px, 4vw, 56px);
  max-width: 64ch;
}

.apps-head h2 {
  display: flex;
  flex-direction: column;
  margin: 0 0 20px;
  line-height: 1.1;
}

.apps-head h2 .en {
  font-weight: 800;
  font-size: clamp(26px, 2.6vw, 34px);
  letter-spacing: -0.02em;
  color: var(--ink);
}

.apps-head h2 .vi {
  font-weight: 400;
  font-size: 13px;
  color: var(--muted);
  font-style: italic;
  margin-top: 6px;
}

.apps-intro {
  margin: 0 0 6px;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-2);
}

.apps-intro-vi {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
  font-style: italic;
}

.app-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.app-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: clamp(20px, 3vw, 40px);
  padding: clamp(20px, 2.4vw, 28px) 0;
  border-bottom: 1px solid var(--line);
}

.app-num {
  font-family: "Be Vietnam Pro", system-ui, sans-serif;
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--muted);
  padding-top: 4px;
}

.app-body {
  min-width: 0;
}

a.app-title,
span.app-title {
  display: inline;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-fast), color var(--t-fast);
}

a.app-title:hover {
  border-bottom-color: var(--ink);
}

.app-meta {
  font-size: 13px;
  font-style: italic;
  line-height: 1.5;
  color: var(--muted);
  margin-top: 6px;
  max-width: 72ch;
}

.app-item.is-soon .app-title {
  color: var(--muted-2);
  font-weight: 600;
}

.app-item.is-soon .app-num {
  color: var(--muted-2);
}

/* ---------- Books page ----------
   Same Swiss/Japanese restraint as the rest of the site. Sharp slabs,
   thin hairlines, EN primary VI secondary. The flipbook preview is
   intentionally small — enough to feel the design, not enough to
   read cover to cover. No zoom, no right-click save, no drag.
   For the full book in clear print, order a copy. */
.topnav a.is-active {
  color: var(--ink);
}
.topnav a.is-active::after {
  transform: scaleX(1);
}

.books-hero {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(48px, 7vw, 96px) var(--pad) clamp(24px, 3vw, 40px);
  text-align: left;
}

.books-title {
  display: flex;
  flex-direction: column;
  margin: 12px 0 20px;
  line-height: 1.05;
}

.books-title .en {
  font-weight: 800;
  font-size: clamp(40px, 6vw, 72px);
  letter-spacing: -0.03em;
  color: var(--ink);
}

.books-title .vi {
  font-weight: 400;
  font-size: 14px;
  color: var(--muted);
  font-style: italic;
  margin-top: 8px;
}

.books-intro {
  max-width: 64ch;
  margin: 0 0 6px;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-2);
}

.books-intro-vi {
  max-width: 64ch;
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
  font-style: italic;
}

.books-section {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(32px, 5vw, 64px) var(--pad) clamp(64px, 8vw, 120px);
  border-top: 1px solid var(--line);
}

.book-entry {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: clamp(28px, 4vw, 64px);
  padding: clamp(36px, 5vw, 64px) 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}

.book-entry:last-child {
  border-bottom: none;
}

/* --- Preview column --- */
.book-preview {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  width: min(560px, 100%);
  flex-shrink: 0;
}

.flipbook {
  position: relative;
  width: min(560px, 100%);
  max-width: 100%;
  background: #fafafa;
  border: 1px solid var(--line);
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
}

.flipbook-img {
  display: block;
  width: 100%;
  height: auto;
  pointer-events: none;
  -webkit-user-drag: none;
  user-select: none;
  -webkit-user-select: none;
}

/* Transparent overlay that sits on top of the image and absorbs
   right-clicks and drags. Controls live OUTSIDE .flipbook so the
   guard doesn't block them. */
.flipbook-guard {
  position: absolute;
  inset: 0;
  background: transparent;
  cursor: default;
}

.flip-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  font-variant-numeric: tabular-nums;
}

.flip-btn {
  width: 28px;
  height: 28px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink-2);
  font-size: 16px;
  line-height: 1;
  cursor: pointer;
  padding: 0;
  border-radius: var(--radius);
  transition: border-color var(--t-fast), color var(--t-fast);
}

.flip-btn:hover {
  border-color: var(--ink);
  color: var(--ink);
}

.flip-counter {
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  min-width: 56px;
  text-align: center;
  letter-spacing: 0.04em;
}

.flip-note {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  margin: 0;
  font-size: 11px;
  text-align: center;
}

.flip-note .en {
  color: var(--muted);
  letter-spacing: 0.04em;
}

.flip-note .vi {
  color: var(--muted-2);
  font-style: italic;
}

/* --- Info column --- */
.book-info {
  min-width: 0;
  max-width: 56ch;
}

.book-kind {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.book-kind .en {
  font-weight: 700;
  color: var(--ink-2);
}

.book-kind .vi {
  font-weight: 400;
  color: var(--muted);
  font-style: italic;
  text-transform: none;
  letter-spacing: 0.02em;
}

.book-title {
  margin: 0 0 8px;
  font-size: clamp(22px, 2.4vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: var(--ink);
}

.book-authors {
  margin: 0 0 18px;
  font-size: 14px;
  font-style: italic;
  color: var(--muted);
}

.book-body {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.65;
  color: var(--ink-2);
}

.book-body-vi {
  margin: 0 0 24px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
  font-style: italic;
}

.book-buy {
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 10px 18px;
  border: 1px solid var(--ink);
  background: #fff;
  color: var(--ink);
  border-radius: var(--radius);
  transition: background var(--t-fast), color var(--t-fast);
}

.book-buy .en {
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.04em;
}

.book-buy .vi {
  font-size: 11px;
  font-style: italic;
  color: var(--muted);
  transition: color var(--t-fast);
}

.book-buy:hover {
  background: var(--ink);
  color: #fff;
}

.book-buy:hover .vi {
  color: var(--muted-2);
}

@media (max-width: 760px) {
  .book-entry {
    grid-template-columns: 1fr;
    justify-items: center;
    gap: 28px;
  }

  .book-info {
    text-align: left;
  }
}

/* ---------- Footer ---------- */
.footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 32px var(--pad) 48px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 12px;
  color: var(--muted);
}

.footer .en {
  font-weight: 600;
  color: var(--ink-2);
}

.footer .vi {
  font-style: italic;
  color: var(--muted-2);
}

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  .topbar {
    grid-template-columns: auto auto;
    grid-template-rows: auto auto;
    row-gap: 12px;
  }

  .topnav {
    grid-column: 1 / -1;
    justify-self: start;
    flex-wrap: wrap;
    gap: 0;
  }

  .topnav a:first-child { margin-left: 0; }

  .brand-vi { font-size: 13px; }
  .brand-en { font-size: 11px; }

  .pillars {
    grid-template-columns: 1fr;
  }

  .pillar + .pillar {
    border-left: none;
    border-top: 1px solid var(--line);
  }

  .pub-item {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .pub-year {
    padding-top: 0;
  }

  .app-item {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .app-num {
    padding-top: 0;
  }
}